The prevalence of bronchodilator responsiveness of the small airway (using mid-maximal expiratory flow) in COPD - a retrospective study

Table 1 Baseline demographics across groups

Variable	Group 1 n = 107	Group 2 n = 79	Group 3 n = 128
Age	60 (54 – 71)^cd	67 (56 – 73)	67 (58 – 74)
Sex (n, %)
Male	71 (67)	40 (50.6)	67 (51.9)
Female	35 (33)	39 (49.4)	62 (48.1)
BMI (kg/m²)	27.75 (23.94 – 31.63)^d	25.89 (22.77 – 31.22)	25.82 (22.13 – 29.69)
Smoking status (n, %)
Current smoker	62 (58.5)	50 (63.3)	81 (62.8)
Ex-smoker	44 (41.5)	29 (36.7)	48 (37.2)
Pack-years ^a	38 (25 – 52)	42 (26 – 54)	40 (25 – 57)
Years quit ^a	7 (2 – 12)	12 (3 – 18)	10 (2 – 20)
Medications (n, %)
SABA or SAMA	62 (58.5)	44 (55.7)	75 (58.1)
SABA + SAMA	0 (0)	1 (1.3)	2 (1.6)
LABA or LAMA	27 (25.5)	16 (20.3)	32 (24.8)
LABA + LAMA	1 (0.9)	2 (2.5)	3 (2.3)
ICS	5 (4.7)	7 (8.9)	6 (4.7)
LABA + ICS	12 (11.3)	10 (12.7)	18 (14)
LABA + LAMA + ICS	13 (12.3)	10 (12.7)	17 (13.2)

Abbreviations: BMI body mass index, SABA short-acting beta-2 agonist, SAMA short-acting muscarinic antagonist, ICS inhaled corticosteroid, LABA long-acting beta-2 agonist, LAMA long-acting muscarinic antagonist, BDR bronchodilator responsiveness, FEV1 forced expiratory volume in one second, MMEF maximal mid-expiratory flow
Legend: Data are presented as median (IQR) or n (%). Group 1, BDR in FEV1 and MMEF; group 2, BDR in MMEF alone; group 3, no BDR in either measure.
^aThis was only assessed in ex-smokers
^bSignificantly different from group 1
^cSignificantly different from group 2
^dSignificantly different from group 3

ISSN: 1471-2466